Dynamics in systematic liquidity

We develop the principal component analysis (PCA) approach to systematic liquidity measurement by introducing moving and expanding estimation windows. We evaluate these methods along with traditional estimation techniques (full sample PCA and market average) in terms of ability to explain (1) cross-sectional stock liquidity and (2) cross-sectional stock returns. For several traditional liquidity measures our results suggest an expanding window specification for systematic liquidity estimation. However, for price impact liquidity measures we find support for a moving window specification. The market average proxy of systematic liquidity produces the same degree of commonality, but does not have the same ability to explain stock returns as the PCA-based estimates.Liquidity (Economics)

Prime ends for domains in metric spaces

In this paper we propose a new definition of prime ends for domains in metric spaces under rather general assumptions. We compare our prime ends to those of Carath\'eodory and N\"akki. Modulus ends and prime ends, defined by means of the \p-modulus of curve families, are also discussed and related to the prime ends. We provide characterizations of singleton prime ends and relate them to the notion of accessibility of boundary points, and introduce a topology on the prime end boundary. We also study relations between the prime end boundary and the Mazurkiewicz boundary. Generalizing the notion of John domains, we introduce almost John domains, and we investigate prime ends in the settings of John domains, almost John domains and domains which are finitely connected at the boundary.Comment: 46 pages, 4 figure

Dynamics in systematic liquidity

We develop a principal component approach to systematic liquidity measurement by introducing moving and expanding estimation windows. We evaluate these methods along with traditional estimation techniques (full sample PCA and market average) in terms of ability to explain (1) cross sectional stock liquidity and cross sectional stock returns. For several traditional liquidity measures our results suggest an expanding window specification for systematic liquidity estimation. The market average proxy of systematic liquidity produces the same degree of commonality, but does not have the same ability to explain stock returns as the PCA-estimates

Does the Kunitz domain from the Alzheimer's amyloid β protein precursor inhibit a kallikrein responsible for post-translational processing of nerve growth factor precursor?

AbstractAlternative splicing of the Alzheimer's amyloid β protein precursor (ABPP) message leads to the production of several variants of this precursor polypeptide. Two of these variants contain a domain that is highly homologous to members of the Kunitz class of protease inhibitors. In order to initiate a study of the physiological role of this domain, we have produced active ABPP Kunitz inhibitor by constructing and expressing a synthetic gene in E. coli. Nerve growth factor (NGF) deficiency has been suggested as a possible cause of the neural degeneration characteristic of Alzheimer's disease, and trypsin and γ-NGF are the two enzymes that have been shown to be capable of processing β-NGF precursor to active, mature β-NGF in vitro, therefore the specificity of purified recombinant ABPP Kunitz inhibitor was analyzed with respect to these two proteases. Binding of isolated ABPP Kunitz domain both to trypsin (Ki,app < 10 nM and to γ-NGF (Ki,app = 300 nM) was observed. This difference in binding to the two proteases correlates with the approximately 20-fold higher rate observed for in vitro processing of the β-NGF precursor by trypsin compared to processing by γ-NGF, indicating that perhaps the inhibitor mimics the interaction of the β-NGF precursor with proteases. The kallikrein actually responsible for β-NGF precursor processing in vivo is unknown, but these results suggest that it is capable of being significantly inhibited by exposure to the ABPP Kunitz domain

Wear of human teeth: a tribological perspective

The four main types of wear in teeth are attrition (enamel-on-enamel contact), abrasion (wear due to abrasive particles in food or toothpaste), abfraction (cracking in enamel and subsequent material loss), and erosion (chemical decomposition of the tooth). They occur as a result of a number of mechanisms including thegosis (sliding of teeth into their lateral position), bruxism (tooth grinding), mastication (chewing), toothbrushing, tooth flexure, and chemical effects. In this paper the current understanding of wear of enamel and dentine in teeth is reviewed in terms of these mechanisms and the major influencing factors are examined. In vitro tooth wear simulation and in vivo wear measurement and ranking are also discussed

SIP Draft Specification

A Submission Information Package (SIP) is defined in the OAIS standard1 as an Information Package that is delivered by the Producer to the OAIS for use in the construction or update of one or more AIPs and/or the associated Descriptive Information. Many different SIP formats are used all over the world and unfortunately there is currently no central format for a SIP which would cover all individual national and business needs identified in the E-ARK Report on Available Best Practices. Therefore, the main objective of this report is to describe a draft SIP specification for the E-ARK project – give an overview of the structure and main metadata elements for E-ARK SIP and provide initial input for the technical implementations of E-ARK ingest tools. The target group of this work are E-ARK project partners as well as all other archival institutions and software providers creating or updating their SIP format specifications. This report provides an overview of: • The general structure for submission information packages. This report explains how the E-ARK SIP is constructed by following the common rules for all other (archival, dissemination) information packages. • The SIP METS Profile. We provide a detailed overview of metadata sections and the metadata elements in these sections. The table with all metadata elements could possibly be of interest to technical stakeholders who wish to continue with the more detailed work of the E-ARK SIP implementation later. Two examples with different kinds of content (MoReq2010, SIARD-E) following the common structure for EARK submission information package can be found in the appendixes to this report

Records export, transfer and ingest recommendations and SIP Creation Tools

This report describes a software deliverable as it delivers a number of E-ARK tools: • ERMS Export Module (a tool for exporting records and their metadata from ERMS in a controlled manner); • Database Preservation Toolkit (a tool for exporting relational databases as SIARD 2.0 or other formats); • ESSArch Tools for Producer (a tool for SIP creation); • ESSArch Tools for Archive (a tool for SIP ingestion); • RODA-in (a tool for SIP creation); • Universal Archiving Module (a tool for SIP creation). In addition, an overview of Pre-Ingest and Ingest processes will be provided by this report which will help to understand the tools and their use

The E-ARK Integrated Platform Reference Implementation

The report describes a set of software components that have been developed in order to realize the E-ARK Integrated Platform Reference Implementation Prototype for storing, searching, and accessing E-ARK Information Packages on a scalable infrastructure. The E-ARK Integrated Platform Reference Implementation Prototype integrates: (a) an Information Package creation and management system, (b) a repository for content search and access, and (c) a scalable storage and execution environment based on Apache Hadoop. The report focuses on the software components that have been individually developed and deployed on top of the core infrastructure components (Hadoop, Lily, SolR). This complements deliverable D6.1 which describes the set-up and configuration of the repository and indexing frameworks. This report accompanies a number of software development results which have been developed in order to realize the Integrated Platform Reference Implementation Prototype. Besides the individual software components, the report provides an overview of the overall system architecture, the integration approach and utilized interfaces